Prosthetic foot with heel and keel springs

ABSTRACT

A keel is provided having a spring portion and a connecting portion. The spring portion can have a split section that is divided into two sections. Each section can have a top open channel formed therein. Each channel is compressible during compression of the keel. A compression member can be placed within each channel to control or limit the amount of keel spring compression. The connecting portion is rigidly connected to a rigid center support. The top of the center support can have a threaded connector, which allows for vertically adjustable connection of an adjacent prosthetic component. A heel is also provided having a spring portion and a connecting portion. The spring portion can have a top open channel formed therein. The channel is compressible during compression of the heel. A compression member can be placed within the channel to control or limit the amount of heel spring compression.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a prosthetic foot, and moreparticularly to a prosthetic foot being adjustable in heel and keelspring capacities for complete customization and personalization, beingadjustably vertically connectable at the ankle joint, and having a rigidangle joint.

2. Description of the Related Art

People frequently are in need of prosthetic limbs as a result ofaccidents, disease or birth defects. The need for quality prostheticfeet is high. There have been many attempts to make suitable prostheticfeet, each desiring to reach goals of safety, functionality and comfort,among other qualities. The existing prosthetic feet have achievedvarying levels of success at attaining each of these stated goals.Further, many strategies have been utilized in designing prostheticfeet. Some designs are relatively noncomplicated, and seek to use asimple design. Other designs are complex, and seek to simulate or copythe structure of the human foot.

One prosthetic foot in particular is made by Freedom Innovations and issold under the name Renegade LP. This foot has an uninterruptedcomponent spanning from the ankle to the toe. A second component extendsfrom the heel to the front of the foot. While this foot may work wellfor its intended purpose, it is not without some limitations. Forexample, there is not a heel spring incorporated into the design.Another limitation of this foot is that there is no way to adjust thelocation of the heel with respect to the residual limb.

Another existing prosthetic foot is sold by Ossur under the name ModularIII. This foot has one uninterrupted component forming the ankle andspanning to the toe area. A heel component depends rearward from themajor component to the heel. This heel component connects to the bottomsurface of the major component. A primary advantage of this foot residesin its simplicity. However, there are drawbacks also associatedtherewith. One limitation is the lack of adjustability of the locationof the heel with respect to the residual limb. A further limitation ofthis foot is the lack of a heel spring.

A third prosthetic foot is shown in U.S. Pat. No. 5,695,527 to Allen.This patent shows a coil prosthetic foot formed by a continuous coilspring having a foot center coil section, a heel extension section and aforefoot extension section. One drawback of the design shown in thispatent is that lack of adjustability of the amounts of flex in the heelextension section and the forefoot extension section. Also, no rigidcenter support is shown in this patent for allowing a strong andvertically adjustable connection to adjacent prosthetic components.

A further prosthetic foot is an assembly that is shown in U.S. Pat. No.6,129,766 to Johnson et al. This patent discloses an ankle member, aheel member pivotally connected to the ankle member, and an elongatemetatarsal-toe member having a rear portion underlying a forward portionof the heel member and projecting forwardly from the heel member. Thisfoot has compressible elements incorporated between the pivotallyconnected members. This foot, being an assembly, is relativelycomplicated when compared to the previously described prosthetic feet. Afurther limitation of this foot is that there may be inherent noiseproblems incorporated into the design of the compressible elements. Thisis evidenced by the presence of, and the need for, noise abatementfeatures being described in the disclosure.

A still further prosthetic foot is sold by Otto Bock under the nameLuXon Max. This foot shows a relatively flat and uninterrupted componentspanning from the ankle location forward to a location above andrearward of the toe location. Distinct heel and toe components areconnected to the bottom of the flat component. One limitation of thisfoot is that there is no way to adjust the location of the heel withrespect to the residual limb. Another limitation of this foot is thatthere is no heel spring incorporated into the design. A gap or channelis apparent between the heel and toe components. The shown gap is opento the bottom of the foot, such that any flex in the foot will cause thesize of the gap to expand or increase. Accordingly, there is no way tocontrol the flexibility or adjust the rate of flexibility shown ortaught in the LuXon Max foot.

Yet another prosthetic foot is shown in U.S. Pat. No. 6,602,295 toDoddroe et al. The foot shown in this patent has a foot plate, which isan uninterrupted plate spanning from heal to toe. A toe spring and aheel spring are provided. The toe spring is forward of the heel spring.The toe spring and heel spring are independently connected to a topplate. Further, the heel spring is rotatably connectable to the topplate and the foot plate.

Another prosthetic foot is shown in U.S. Pat. No. 6,241,776 toChristensen. The foot shown in this patent has a forefoot reinforcementmember extending from an attachment section, through a curvilinearspring and arch section, to a toe end. A heel member extends from thearch section to the heel end. The strength and energy return in thisfoot is due to the flexing of the members. A limitation of this foot isthat it is lacking is adjustability. A further limitation is that itdoes not have a heel spring.

Another prosthetic foot is shown in U.S. Pat. No. 5,037,444 to Phillips.That patent shows a foot with a forefoot portion and a demountablyconnected heel portion. At toe-off, the energy return is created fromenergy stored during the flexing of the forefoot member. One limitationis that the foot of this invention does not have a heel spring. Afurther limitation is the lack of adjustability of the location of theheel.

A still further prosthetic device is shown in U.S. Pat. No. 5,545,234 toCollier, Jr. This patent shows a modular foot with a heel section and anelongate midfoot section. The heel and midfoot sections are configuredfor detachable combination via a coupling joint. A foot with adifferential stiffness characteristic is provided due to a heel sectionbeing formed of a material with a first predetermined stiffnesscharacteristic and a midfoot section being formed from a material of asecond predetermined stiffness characteristic. One drawback of materialswith predetermined stiffness characteristic is the lack ofadjustability.

Thus there exists a need for a prosthetic foot that solves these andother problems.

SUMMARY OF THE INVENTION

The present invention relates to a prosthetic foot, and moreparticularly to a prosthetic foot being adjustable in heel and keelspring capacities for complete customization and personalization, beingadjustably vertically connectable at the ankle joint, and having a rigidangle joint. In a preferred embodiment, a keel is provided. The keel canhave a spring portion and a connecting portion. The spring portion canhave a split section that is divided into two sections. Each section canhave a top open channel formed therein. Each channel is compressibleduring compression of the keel. A compression member can be placedwithin each channel to control or limit the amount of keel springcompression. The channels and compression members can be of any selectedsize and shape, and can have one of several modes of operation. Theconnecting portion is rigidly connected to a rigid center support. Thekeel can be connected to the back of the center support. The centersupport can also have a front, a top and a bottom. The top of the centersupport can have a threaded connector, which allows for verticallyadjustable connection of an adjacent prosthetic component. A heel isalso provided. The heel can have a spring portion and a connectingportion. The spring portion can have a top open channel formed therein.The channel is compressible during compression of the heel. Acompression member can be placed within the channel to control or limitthe amount of heel spring compression. The compression member can be ofany selected size and shape, and can have one of several modes ofoperation.

According to one aspect of the present invention, the keel can be aforward opening, or forward facing, keel. Also, the heel can be arearward opening heel. The keel can have a rear that is rearward of thefront of the heel. The keel and heel can each have a respective springportion. The foot spring, being comprised of the keel spring and heelspring, can be crossed. The keel and heel can be separated by a rigidcenter support.

According to another aspect of the present invention, the center supporthas a connector than allows an adjacent component to be verticallyadjustably connected to the foot. This results in the practitioner beingable to adjustably select the location of the heel with respect to theresidual limb. The location of the heel with respect to the connectorcontributes to overall length of the prosthetic limb, and can affectgate. Further, varying the location of the heel will affect the amountof flexing and deflection of the heel strike and compression of the heelspring at heel-strike. This adjustability results in the foot being moreproperly positioned given the needs and uses of a particular person.

Another advantage of the prosthetic foot of the present invention isthat the foot spring is comprised of the keel spring and the heelspring. In this regard, the keel spring and heel spring are coactingsprings even though they can be separated by a rigid center support.Further, the keel spring, or at least a portion thereof, is locatedrearward of at least a portion of the heel spring. This advantageouslyallows for increased space for spring compression of the keel spring andheel spring in the limited space of the prosthetic foot.

Related, a further advantage of the prosthetic foot of the presentinvention is that the present invention provides support to the personat mid-stance. This is accomplished by flexing of the keel and heel, andof compression of the keel spring and the heel spring. This flexing andcompression relieve problems that may normally be associated with flatfoot. Further, the energy in the heel strike and heel spring is usefulin propelling the foot towards toe-off, and, alternatively, the energyin the keel and keel spring can be useful in assisting the person ontothe heel strike if the person chooses to rock backwards.

A still further advantage of an embodiment of the present invention isthat the spring portions of the keel and heel, respectively, are adaptedto removably receive compression members. In this regard, the relativestiffness of the springs can be adjusted. Related, a channel is formedinto each of the two side pieces in the split section of the keelspring. Each side can receive a compression member of a differentstiffness.

In an alternative embodiment, the compression members can be permanentlyreceived within the heel and keel and the stiffness of the compressionmembers can be adjusted. The stiffness can be adjusted via changing theair pressure or by adjusting electro-mechanical hardware embedded withinthe compression members.

A further advantage yet of the prosthetic foot of the present inventionis that the present invention is free of sharp angles. Sharp angles in aprosthetic foot can lead to stress concentrations. Avoiding stressconcentrations decreases the likelihood of failure of the foot.

A still further advantage yet of the present invention is that it iscustomizable to suit the specific needs of a given person. The heel andkeel blades are removably connected to the center support, and theblades can be easily interchanged.

Other advantages, benefits, and features of the present invention willbecome apparent to those skilled in the art upon reading the detaileddescription of the invention and studying the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of the prostheticfoot of the present invention.

FIG. 2 is a side view of the preferred embodiment shown in FIG. 1.

FIG. 3 is a rear view of the preferred embodiment shown in FIG. 1showing the heel.

FIG. 4 is a front view of the preferred embodiment shown in FIG. 1showing the keel.

FIG. 5 is a top view of the preferred embodiment shown in FIG. 1.

FIG. 6 is a bottom view of the preferred embodiment shown in FIG. 1.

FIG. 7 is a cross-sectional side view of the preferred embodiment shownin FIG. 2 and taken along line 7-7.

FIG. 8 is a perspective view of a preferred ankle top.

FIG. 9 is a perspective view of a preferred ankle bottom.

FIG. 10 is a perspective view of a preferred heel washer.

FIG. 11 is a perspective view of a preferred keel washer.

FIG. 12 is a perspective view of an alternative embodiment of thepresent invention.

FIG. 13 is a cross-sectional view of the preferred embodiment shown inFIG. 12 and taken along line 13-13.

FIG. 14 is a side view of the operation of a preferred embodiment of theprosthetic foot of the present invention at heel-strike.

FIG. 15 is a side view of the operation of a preferred embodiment of theprosthetic foot of the present invention at mid-stance.

FIG. 16 is a side view of the operation of a preferred embodiment of theprosthetic foot of the present invention at toe-off.

FIG. 17 is a side view of a preferred embodiment of the presentinvention showing an adjacent component vertically adjustably connectedthereto.

FIG. 18 is partially-exploded side view of an alternative preferredembodiment of the present invention.

FIG. 19 is a perspective view showing an alternative compression member.

FIG. 20 is a perspective view showing a further alternative compressionmember.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the invention will be described in connection with severalpreferred embodiments, it will be understood that it is not intended tolimit the invention to those embodiments. On the contrary, it isintended to cover all alternatives, modifications and equivalents as maybe included within the spirit and scope of the invention as defined bythe appended claims.

Looking first to FIGS. 1-7, it is shown that a prosthetic foot 10 isprovided. The foot 10 is generally comprised of a rear portion 11 and afront portion 12. A foot spring 13 is provided between the front andrear of the foot 10. In this illustrated embodiment, the foot spring 13generally has scissor shape. However, it will be understood that thefoot spring 13 could have other shapes without departing from the broadaspects of the present invention. The prosthetic foot 10 of the presentinvention has a longitudinal axis 15 spanning the length of the foot.The longitudinal axis 15 is generally parallel with the ground when thefoot rests on the ground during zero load conditions. When viewed fromabove, the prosthetic foot has a right side 16 and a left side 17.

A keel 20 is provided according to this illustrated embodiment. The keel20 has two portions, a spring portion 25 and a connecting portion 60.Each of these portions is described in detail below. One suitablematerial is sold under the name Delron and is sold by Dupont. It isunderstood that other materials could be utilized without departing fromthe broad aspects of the present invention. In the illustratedembodiment, the keel 20 is shown to be a unitary piece.

The spring portion 25 has a first end 26 and an opposed second end 27. Afirst surface 28 is provided as is an opposed second surface 29. Viewingthe spring portion 25 from the side, surface 28 is the top surface andsurface 29 is the bottom surface. A toe portion 30 is at the front ofthe spring portion 25 at the first end 26. A split section 31 is betweenthe toe portion 30 and the second end 27 of the spring portion 25. Thesplit section 31 comprises a first side piece 32 and a second side piece35. The first side piece 32 has a first end 33 and a second end 34. Thesecond side piece 35 has a first end 36 and a second end 37. The firstside piece 32 and the second side piece 35 are separated by an opening38. The bottom of the spring portion, surface 29, is preferably radiusedor curved. Surface 28 is preferably generally planar. Yet, it isappreciated that surface 29 could be non-planar without departing fromthe broadest aspects of the present invention.

A channel 40 is preferably formed into the first side section 32 of thespring portion 25. The channel 40 is preferably open to surface 28.Channel 40 has a top 41, a bottom 42, side 43 and side 44. The profileof channel 40 is generally circular, and can have a neck at the top 41that is narrower than the diameter of the circular profile. In thisregard, a compression member 45 can be removably received within channel40. One preferred compression member is made of urethane. Yet, it isappreciated that other suitable elastically compressible materials couldbe utilized without departing from the broad aspects of the presentinvention. Compression member 45 can dampen or slow the rate and amountthat channel 40 can compress under a load condition caused by flexing ofthe keel 20. A practitioner can interchange between compression members45 of a desired stiffness to achieve flexing characteristics per thepatients needs.

A channel 50 is preferably formed into the second side section 35 of thespring portion 25. The channel 50 is preferably open to surface 28.Channel 50 has a top 51, a bottom 52, side 53 and side 54. The profileof channel 50 is generally circular, and can have a neck at the top 51that is narrower than the diameter of the circular profile. In thisregard, a compression member 55 can be removably received within channel50. One preferred compression member is made of urethane. Yet, it isappreciated that other suitable elastically compressible materials couldbe utilized without departing from the broad aspects of the presentinvention. Compression member 55 can dampen or slow the rate and amountthat channel 50 compresses under a load condition caused by flexing ofthe keel 20. A practitioner can interchange between compression members55 of a desired stiffness to achieve flexing characteristics per thepatients needs.

It is appreciated that the relative stiffness of compression members 45and 55 can differ, such that the first side piece 32 and the second sidepiece 35 of the spring portion can have distinct flexuralcharacteristics.

The keel 20 also has a connecting portion 60. Connecting portion 60 isconnected to a center support 110, described below. Connecting portion60 has a first lug 61 with a top 62 and a bottom 63. Connecting portion60 further has a second lug 64 with a top 65 and a bottom 66. Lug 61 ispreferably integral with the first side piece 32 of the foot spring 25.Lug 64 is preferably integral with the second side piece 35 of the footspring.

A heel 70 is also provided according to the preferred illustratedembodiment. The heel 70 has two portions, a spring portion 75 and aconnecting portion 100. Each of these portions is described in detailbelow. One suitable material is sold under the name Delron and is soldby Dupont. It is understood that other materials could be utilizedwithout departing from the broad aspects of the present invention. Inthe illustrated embodiment, the heel 70 is shown to be a unitary piece.

The spring portion 75 has a first end 76 and an opposed second end 77. Afirst surface 78 is provided as is an opposed second surface 79. Viewingthe spring portion 75 from the side, surface 78 is the top surface andsurface 79 is the bottom surface. The spring portion 75 has a first side80 and a second side 81. A heel strike 82 is preferably at the secondend 77 of the spring portion 75. The bottom of the spring portion,surface 79, is preferably radiused or curved. Surface 78 is preferablygenerally planar. Yet, it is appreciated that surface 79 could benon-planar without departing from the broadest aspects of the presentinvention.

A channel 90 is preferably formed into the spring portion 75. Thechannel 90 is preferably open to surface 78. Channel 90 has a top 91, abottom 92, side 93 and side 94. The profile of channel 90 is generallycircular, and can have a neck at the top 91 that is narrower than thediameter of the circular profile. In this regard, a compression member95 can be removably received within channel 90. One preferredcompression member is made of urethane. Yet, it is appreciated thatother suitable elastically compressible materials could be utilizedwithout departing from the broad aspects of the present invention.Compression member 95 can dampen or slow the rate and amount thatchannel 90 can compress under a load condition caused by flexing of theheel 70. A practitioner can interchange between compression members 95of a desired stiffness to achieve flexing characteristics per thepatients needs.

The connecting portion 90 of the heel 70 has a top 91 and a bottom 92.

The center support 110 is preferably comprised of four components, plusa fastener. Those parts include an ankle top 120, an ankle bottom 130that mates with the ankle top 120, a keel washer 140 and a heel washer150. Each of these components is described below. One suitable fastenerincludes a bolt 160 and a nut 170. Yet, it is understood that otherfasteners can be utilized without departing from the broad aspects ofthe present invention. The center support 110 is preferably a rigidsupport, and is preferably constructed of metal components.

Turning now to FIG. 8 in particular, the ankle top 120 is illustrated.The ankle top 120 has a top 121 and a bottom 122, a front 123 and a rear124, and a first side 125 and a second side 126. Ankle top 120 furtherhas four lugs 126 projecting down from the bottom 122 of the ankle top120. A connector 128 projects upward from the top 121 of the ankle top120. The connector 128 is preferably externally threaded with threads129.

Turning now to FIG. 9 in particular, the ankle bottom 130 isillustrated. The ankle bottom 130 has a top 131 and a bottom 132, afront 133 and a rear 134, and a first side 135 and a second side 136.Ankle bottom further has four holes 137 formed through the top 131 formating with lugs 126 of the ankle top 120. A hole 138 is through thefront 133 and a hole 139 is through the rear 134. Holes 138 and 139 arealigned such that bolt 160 can be inserted through the holes. Screws canbe used to connect the ankle top 120 and the ankle bottom 130. The rear124 of the ankle top 120 overhangs the rear 134 of the ankle bottom 130when these two components are connected to each other, as seen in FIG.1.

Turning now to FIG. 11, the keel washer 140 is illustrated. The keelwasher 140 has a top 141 and a bottom 142, a front 143 and a rear 144,and a first side 145 and a second side 146. A cuff 147 is on the front143 of the keel washer preferably spanning from the top 141 to thebottom 142. A hole 148 is provided through the keel washer 140 forreceiving bolt 160.

Turning now to FIG. 10, the heel washer 10 is illustrated. The heelwasher 150 has a top 151 and a bottom 152, a front 153 and a rear 154,and a first side 155 and a second side 156. A lip 157 is projectsgenerally perpendicularly rearward from the top 151 of the heel washer150. A hole 158 is provided through the heel washer 150 for receivingbolt 160.

Looking again to FIGS. 1-7, assembly of the preferred illustratedembodiment of the prosthetic foot 10 is illustrated. The keel 20 isconnected to the center support 110. This is accomplished by having theconnecting portion 60 be located between the ankle bottom 130 and thekeel washer 140. The cuff 147 of the keel washer 140 separates the firstlug 61 and the second lug 64 of the connecting portion. The top 62 oflug 61 and the top 65 of lug 64 is adjacent the top 131 of the anklebottom 130. The rear 124 of the ankle top 120 overhangs the tops 62 and65 of the lugs. Bolt 160 forces the keel 20 to remain contained by theankle top 120, the ankle bottom 130 and the keel washer 140.

The heel 70 is also connected to the center support 110. This isaccomplished by having the connecting portion 100 be located between theankle bottom 130 and the heel washer 150. The lip 157 of the heel washer150 overhangs the top 101 of the connecting portion 100. Bolt 160 forcesthe heel 90 to remain contained by the ankle bottom 130 and the heelwasher 150.

It is appreciated that bolt 160 passes through hole 148 of the keelwasher, holes 138 and 139 of the ankle bottom 130 and hole 158 of theheel washer 150. Nut 160 mates with bolt 160 to maintain a compressionlock on the heel 70 and the keel 20.

The keel 20, as noted above, preferably has a first side piece 32 and asecond side piece 35 with an opening 38 there between. In this regard,it is preferably that the heel pass through the opening 38 in the keel20. This pass-between of the heel 70 through the keel 20 creates a footspring 13 of a vertical shock absorbing nature.

Turning now to FIG. 17, it is illustrated how an adjacent prostheticcomponent is vertically adjustably connected to the foot 10. In theillustrated embodiment, a clamp 180 is provided. The clamp 180 has afirst end 181 that is internally threaded with threads 182, and a secondend 183 that is internally threaded with threads 184. The desiredlinearly vertical offset is determined, the component 180 is rotatedabout the threaded connector 128 until a desired offset is achieved, andthen the component is locked in place.

The prosthetic foot 10 can be inserted into a shell (not shown) orcosmetic cover that resembles natural foot. The shell can be used fordirect contact with the ground or for insertion into a shoe (not shown).It will be understood for the sake of clarity, that the operation of theprosthetic foot 10 of the present invention is hereafter described insome circumstances as being in direct relation to the ground or asurface without showing the shell.

Looking now more particularly to operation of the illustrated preferredembodiment, attention is called to FIGS. 14-16. FIG. 14 is illustrativeof loading conditions at heel-strike. At heel-strike, the heel strike 82makes initial contact with the ground, and the front foot portion 12 isoff the ground completely. The heel strike 82 flexibly deflects upwardand the heel spring 75 compresses. The deflection of the heel strike 82is severe, especially when the person is heavy or when the person runsor jumps, or otherwise has a lot of momentum that needs to be absorbedby the foot 10. Energy is stored in the deflected and compressed heelspring 75. The keel 20 is not deflected during in heel-strike, but maybe moved slightly. It is appreciated that the greatest compressionoccurs at the channel 90. This is due to the thickness of the heelspring portion 75 being thinnest at the channel 90. In this regard, whenthe heel spring 75 flexes, the channel 90 will compress such that itbecomes smaller. The greatest amount of flex will occur when nocompression member 95 is present in the channel 90. The stiffness of anycompression member 95 received within channel 90 will control the amountand rate of flex in the heel spring 75 and deflection of the heel strike82.

As the person moves toward mid-stance, the heel spring 75 releases someof its stored energy to assist in propelling the foot 10 to themid-stance position and assist in raising the person upwards.

An operational view at mid-stance is provided in FIG. 15. At mid-stance,the heel strike 82 and the toe section 30 of the keel 20 both contactthe ground, and are both moderately deflected. Further, the foot spring13 is moderately compressed. If the person chooses to rock back onto theheel strike 82, the keel spring 25 decompresses or reflexes to assistthe person in rocking backwards. Conversely, if the person chooses tomove towards toe-off, the heel spring 75 releases energy to assist theperson towards toe-off.

It is noteworthy, that if the person happens to land in a flat footorientation, the toe section 30 and the heel strike 82 may deflectseverely under the flexing of the keel 20 and heel 70, respectively, andthe foot spring 13 may compress severely, while absorbing the shock, andthen release some energy to return the foot to mid-stance equilibrium.

FIG. 16 shows an operational view of the present invention at toe-off.At toe-off, the front end 26 of the keel is the only part of the footthat is contacting the ground. The toe section 30 is severely deflectedand keel spring portion 25 is compressed. The heel strike 82 is notdeflected during toe-off. The spring portion 25 of the keel 20 releasesenergy during toe-off. It is appreciated that the greatest compressionoccurs at the channels 40 and 50 of the first side piece 32 and thesecond side piece 35, respectively. This is due to the thickness of thekeel spring portion 25 being thinnest at the channels 40 and 50. In thisregard, when the keel spring 25 flexes, the channels 40 and 50 willcompress such that they become smaller. The greatest amount of flex willoccur when no compression members 45 and 55 are present in the channels40 and 50, respectively. The stiffness of any compression memberreceived within channels 40 or 500 will control the amount and rate offlex in the keel spring 25 and deflection of the toe section 30 of thespring portion 25.

Turning now to FIGS. 12 and 13, it is seen that an additional preferredembodiment is illustrated. This embodiment of a foot 210 is similar tofoot 10 described above, in that a keel 220 is provided having a springportion 225 and a connecting portion 240. A heel 250 is also providedhaving a spring portion 255 and a connecting portion 270. A centersupport 280 is provided as well. The center support 280 has an ankle top290 with a connector 298 on the top of the ankle top 290. The connector298 is preferably internally threaded with threads 299. A clamp isprovided for securing an adjacent prosthetic component within theconnector 298 at a selected vertical offset alignment. The offsetalignment is adjusted by rotating the adjacent prosthetic componentwithin the connector 298 to produce vertically linear travel.

An ankle bottom 300, a keel washer 310 and a heel washer 320 are alsoprovided according to the preferred alternative embodiment shown inFIGS. 12 and 13. A bolt 330 mated with nut 331 are shown for compressingon the foot to maintain the engagement of the keel 220 between the keelwasher 310 and the ankle bottom 300, and the heel 250 between the heelwasher 320 and the ankle bottom 300.

Turning now to FIG. 18, a further preferred embodiment of the prostheticfoot 410 of the present invention is illustrated. Foot 410 preferablyhas a keel 420 that is connected to the rear of a center support. Thecenter support has an ankle top and an ankle bottom, and a keel washer.The keel 420 has a spring portion and a connecting portion. Theconnecting portion is received and connected to the center support bybeing contained by the ankle bottom, the ankle top and the keel washer.

The keel 420 is illustrated to have several channels 421, 423 and 425formed therein. Channel 421 is shown to comprise of a series of slots. Acompression member 422 is shown for mating with the channel 421. Thecompression member 422 is internally adjustable. In this regard, apractitioner can remove a desired number of tabs such that the remainingtabs are received within the corresponding slots in the channel 421. Inthe illustrated embodiment, two tabs have been removed from thecompression member 422 in order to achieve desired flexuralcharacteristics in the spring portion of the keel 420. It is understoodthat overall stiffness associated with compression member 422 isdetermined both on the relative stiffness of the material and on thenumber of tabs removed from the strip.

The keel 420 is also shown to have a channel 423, which is similar tothe channels described above. Channel 423 is shaped to removably receivecompression member 424.

The keel 420 is further shown to have a channel 425 formed therein forreceiving compression member 426. In this illustrated embodiment,channel 425 is shown to have a generally square profile.

It is understood that the location of the channels 421, 423 and 425 canvary along the keel spring portion of the keel 420.

A heel 430 is shown to be connected to the keel 420. In this preferredembodiment, the heel 430 is preferably integral and permanently joinedwith the keel 420. Two channels 431 and 433 are illustrated. Channel 431is shown to have a round diameter and can removably receive a roundcompression member 432. Channel 433 is shown to have a generallytrapezoidal profile, and can removably receive a generally trapezoidalshaped compression member 424.

In this preferred illustrated embodiment, the size, location and shapeof the removable compression members are taught to be variable. Thebroadest aspects of the present invention are not limited to theillustrated shapes. Rather, the illustrated sizes and shapes areprovided for illustrative purposes. Each of the compression members inthe illustrated embodiment of the foot 410 are shown to be removablyreceived within their respective channels. The rate and amount of flexof the keel 420 and heel 430 are adjustable. The heel and keel flexingcharacteristics are adjusted by selecting compression members of desiredstiffness and shape, and by selecting mating the compression members inthe channels at desired location.

It is also understood that it is possible for the heel to be connectedto the center support and have the keel be connected to the heel, eventhough such a preferred embodiment is not specifically shown in thefigures.

Turning now to FIG. 19, a further preferred foot 510 is illustrated.Foot 510 has a keel 520 with a spring portion 525 and a connectingportion 535. The spring portion 525 has a first side piece 526 with atop surface 527 and a second side piece 528 with a top surface 529. Afirst compression member 530 is embedded within the first side piece526. A second compression member 531 is also provided. Compressionmember 531 is embedded within the second side piece 528. A discussion ofthe embedded compression members 530 and 531 appears below.

A heel 540 is also illustrated. Heel 540 has a spring portion 541 and aconnecting portion 545. The spring portion has a top surface 542. Acompression member 543 is embedded within the spring portion 541 of theheel 540.

A center support 550 is further provided. The center support 550 has atop 551 and a bottom 552, and a keel washer 553 and a heel washer 554.As with previously described preferred embodiments, the keel 520 andheel 540 are connected to the center support 550.

Compression members 530, 531 and 543 preferably comprise air pockets(not shown) that can be selectably inflated and deflated. Inflation ofthe compression members results in a stiffer compression member, andtherefore reduces that amount and rate of flex within the keel 520 andheel 540, respectively. It is understood that each compression membercan be inflated to a different pressure to provide a foot 510 withunique flex characteristics to the satisfaction of the patient.

Turning now to FIG. 20, a further preferred foot 610 is illustrated.Foot 610 has a keel 620 with a spring portion 625 and a connectingportion 635. The spring portion 625 has a first side piece 626 with atop surface 627 and a second side piece 628 with a top surface 629. Afirst compression member 630 is embedded within the first side piece626. A second compression member 631 is also provided. Compressionmember 631 is embedded within the second side piece 628. A discussion ofthe embedded compression members 630 and 631 appears below.

A heel 640 is also illustrated. Heel 640 has a spring portion 641 and aconnecting portion 645. The spring portion has a top surface 642. Acompression member 643 is embedded within the spring portion 641 of theheel 640.

A center support 650 is further provided. The center support 650 has atop 651 and a bottom 652, and a keel washer 653 and a heel washer 654.As with previously described preferred embodiments, the keel 620 andheel 640 are connected to the center support 650.

Compression members 630, 631 and 643 preferably compriseelectro-mechanical compression members that are adjustably compressible.In the preferred embodiment, a remote control can send an electronicsignal to each compression member with instructions to increase ordecrease stiffness. The compression members, in turn, will receive thesignal and act accordingly. One preferred embodiment can electronicallyalter a mechanical loading of a spring or the like to adjust thestiffness of the compression member. It is understood that otherstructures can be used to accomplish this goal. It is understood thateach compression member can be independently adjusted to a selectedstiffness to provide a foot 610 with unique flex characteristics to thesatisfaction of the patient.

Thus it is apparent that there has been provided, in accordance with theinvention, a prosthetic foot that fully satisfies the objects, aims andadvantages as set forth above. While the invention has been described inconjunction with specific embodiments thereof, it is evident that manyalternatives, modifications, and variations will be apparent to thoseskilled in the art in light of the foregoing description. Accordingly,it is intended to embrace all such alternatives, modifications, andvariations as fall within the spirit and broad scope of the appendedclaims.

1. A prosthetic foot comprising: a rigid center support having a topwith a connector, a bottom, a front and a rear; a heel having an upwardoriented heel channel formed therein, wherein said heel channel extendsfully across said heel and compresses during flexing of said heel; akeel having an upward oriented keel channel formed therein, wherein saidkeel channel extends fully across said keel and compresses duringflexing of said keel, and said keel is connected to said rigid centersupport at said rear of said center support, said keel having a firstside piece and a second side piece with an opening there between, saidfirst side piece having a first side piece channel formed therein andsaid second side piece having a second side piece channel formedtherein, said first side piece channel and said second side piecechannel comprising said upward oriented keel channel.
 2. The prostheticfoot of claim 1 further comprising: a first compression member receivedwithin said heel channel for decreasing the amount and rate of flex ofsaid heel; and a second compression member received within said keelchannel for decreasing the amount and rate of flex of said keel.
 3. Theprosthetic foot of claim 2 wherein: the selected dimensions of said heelchannel is one of round, square, trapezoidal and series of slots; andthe selected dimensions of said keel channel is one of round, square,trapezoidal and series of slots.
 4. The prosthetic foot of claim 2wherein said first compression member is made of urethane with a firstselected stiffness and said second compression member is made ofurethane with a second selected stiffness.
 5. The prosthetic foot ofclaim 2 wherein said first compression member and said secondcompression member, respectively, have a stiffness that is controlled byvarying the air pressure within said first compression member and saidsecond compression member.
 6. The prosthetic foot of claim 1 wherein:said first side piece channel receives a compression member of a firststiffness; and said second side piece channel receives a compressionmember of a second stiffness.
 7. The prosthetic foot of claim 1 whereinsaid heel is connected to said rigid center support at said front ofsaid center support, said heel passing between said first side piece andsaid second side piece of said keel.
 8. The prosthetic foot of claim 1wherein said connector comprises threads, whereby an adjacent componentis vertically adjustable relative said heel and said keel.